The invention relates to wet cell storage battery manufacture, and more particularly to an improved method and machine for enveloping battery plates in separator material.
In an automotive type battery it is often desirable to have either the positive or the negative battery plates enclosed within an envelope. In addition to physically separating and insulating the plates, which normally are grids supporting lead oxide or other material, from one another, the envelopes prevent material from falling to the bottom of the battery case as can happen in conventional batteries utilizing sheet-type separators. Such material accumulating in the bottom of the battery case eventually causes shorts to develop, and the life of the battery is shortened. By containing the material from the plates on which they are positioned, the envelope-type separators avoid this problem. They also enable the battery to be somewhat smaller, since space normally provided below the plates for accumulation of sediment may be eliminated.
The material used for the separator envelope varies, but in general it must have some type of rib structure for holding most of its area away from the plate and it must be porous enough so that the acid and the ions can migrate in and out of the envelope from plate to plate.
Although these envelope-type battery plate separators have been in use in the past, particularly in the so-called "maintenance free" batteries, the separator envelopes have not been formed and assembled onto the battery plates in as efficient and economical a manner as that of the present invention described below.